Systems and methods Utilizing Patient-Matched Instruments

ABSTRACT

Patient-matched surgical instruments, and methods for making patient-matched surgical instruments, may include patient-matched surgical instruments having an anatomy facing side with several discrete, physically separate anatomy contacting portions configured to match the anatomy of a particular patient. The anatomy contacting portions may be one or more of non-uniform in distribution, non-uniform in shape or non-uniform in surface area.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser.No. 61/393,643 filed Oct. 15, 2010 for “Patient-Matched InstrumentsHaving Non-Continuous Contact Surfaces,” U.S. Provisional ApplicationSer. No. 61/402,095 filed Aug. 23, 2010 for “Patient-MatchedInstrumentation,” and U.S. Provisional Application Ser. No. 61/353,838filed Jun. 11, 2010 for “Patient-Matched Instruments Having TexturedContact Surfaces, Methods for Using the Same, and Methods for Making theSame,” the entire contents of each of which are incorporated byreference into this application.

RELATED FIELDS

Surgical instruments and methods for the treatment of bones or joints,in some instances surgical instruments which are matched to a particularpatient's anatomy, are described herein. Also described are methods ofdesigning and using such surgical instruments.

BACKGROUND

Conventional patient-matched instruments are provided with largesurfaces that are configured to conform to a patient's unique anatomy.Successful surgical outcomes depend on the ability of patient-matchedinstruments to provide a reproducible, “confident” 3D-fit between thepatient-matched instrument and the anatomy that they are designed torest against. If there is any doubt by an end user that apatient-matched instrument fits well upon repeated engagement with apatient's unique anatomy, or if the instrument appears to fit well withthe patient's anatomy in multiple spatial orientations with respect tothe anatomy, the instrument is typically discarded, and the surgery iscarried out with the use of conventional, non-patient specificinstruments.

To date, at least some patient-matched surgical instruments for use intotal knee arthroplasty have employed anatomy-contacting surfaces thatare substantially “negatives” of distal femoral and proximal tibialarticular joint surfaces. The anatomy-contacting surfaces are generallylarge surface areas that conform in a continuous manner to substantialareas of a patient's anatomy. In some instances, the custom surgicalinstruments are provided by obtaining 3D image data of the patient'sanatomy (e.g., via an MRI scan), segmenting the 3D image data to clearlydelineate surfaces of the bony and/or cartilegeneous anatomy fromsurrounding tissues, converting the segmented data to a computer modelvia CAD or other software, performing one or more optional secondaryprocesses (e.g., smoothing functions), using a computer model tocustomize one or more surfaces of an instrument to the patient'sanatomy, and manufacturing the custom instrument such that it is adaptedto conform to the patient's anatomy in a single spatial orientation.

In at least some current practices, substantially all portions of thejoint anatomy shown in each 3D image data slice are segmented andconventional patient-matched instruments are provided withanatomy-contacting portions that contact substantially continuous areasof the patient's anatomy. Such anatomy-contacting portions have largecontinuous surface areas of contact with the patient's bone andcartilage, and therefore, it is critical that the engineers or automatedprograms creating the patient-matched instruments maintain a high levelof accuracy and precision throughout each step of the entiresegmentation process. Even if only one or two points onanatomy-contacting surfaces of a patient-matched instrument areinaccurate, misaligned, or otherwise misrepresent the true uniqueanatomy of the patient, the patient-matched instrument may not fit well,sit proud, teeter, wobble, or may not fit at all. In such instances, anend user is less likely to use the instrument. In many cases, poorpatient-matched instrument fit may be attributed to even a few minorerrors in the segmentation process.

Another drawback to using at least some conventional patient-matchedinstruments is that smooth anatomy-contacting surfaces potentially allowthe instruments to slide or slip when engaged with the patient's uniqueanatomy. For example, in some instances, body fluids in combination withslippery bone and cartilage may work against frictional forces betweenthe instruments and anatomical portions. Moreover, due to thehighly-conforming nature of conventional patient-matched instruments,improper seating may be exhibited when used with anatomy having anabundance of osteophytes, legions, or tumors. Lastly, soft tissue (e.g.,fatty tissues) may gather between patient-matched blocks and bone orcartilage and create a false impression to a user that the instrument isseated properly, when it is in fact, the contrary.

SUMMARY

Embodiments of the present invention include patient-matchedinstruments, such as cutting guides used in knee arthroplastyprocedures, which include one or more anatomy contacting portions thatare customized from patient-specific imaging or other types ofpatient-specific data to match the anatomy of the particular patient,and thus facilitate proper position and orientation of thepatient-matched instrument relative to the patient's specific anatomyduring a surgical procedure.

In some embodiments, there is provided a patient-matched surgicalinstrument matched to the anatomy of a particular patient, comprising:an anatomy facing side; wherein the anatomy facing side includes aplurality of discrete, physically separate anatomy contacting portions,the plurality of anatomy contacting portions configured to match theanatomy of the particular patient; wherein the anatomy facing sideincludes a plurality of discrete, physically separate recessed portions,wherein the plurality of recessed portions are recessed relative toparts of the anatomy contacting portions proximate the plurality ofrecessed portions; wherein the plurality of anatomy contacting portionsare at least one of: non-uniform in distribution; non-uniform in shape;or non-uniform in surface area.

In some embodiments, there is further provided a pliant material locatedin at least one of the plurality of recessed portions.

In some embodiments, the plurality of anatomy contacting portionsdefines a first total area of the anatomy facing side and wherein the atleast one recessed portion defines a second total area of the anatomyfacing side; wherein the second total area is greater than the firsttotal area.

In some embodiments, the patient-matched surgical instrument is afemoral cutting guide, wherein the anatomy facing side includes apatella-femoral groove portion, an intercondylar notch portion, a medialcondyle portion, and a lateral condyle portion; wherein the plurality ofanatomy contacting portions comprise at least one anatomy contactingportion proximate the patella-femoral groove portion, at least oneanatomy contacting portion proximate the intercondylar notch portion, atleast one anatomy contacting portion proximate the medial condyleportion, and at least one anatomy contacting portion proximate thelateral condyle portion.

In some embodiments, a total area of the anatomy contacting portionsproximate the patella-femoral groove portion and the intercondylar notchportion is greater than a total area of the anatomy contacting portionsproximate the medial condyle portion and the lateral condyle portion.

In some embodiments, a total area of the anatomy contacting portionsproximate the patella-femoral groove portion and the intercondylar notchportion is less than a total area of the anatomy contacting portionsproximate the medial condyle portion and the lateral condyle portion.

In some embodiments, a density of anatomy contacting portions proximatethe patella-femoral groove portion and the intercondylar notch portionis greater than a density of anatomy contacting portions proximate themedial condyle portion and the lateral condyle portion.

In some embodiments, the plurality of anatomy contacting portionscomprise at least one anatomy contacting portion defining an areacontact.

In some embodiments, the plurality of anatomy contacting portionsfurther comprise at least one anatomy contacting portion defining asubstantially linear contact.

In some embodiments, the plurality of anatomy contacting portionsfurther comprise at least one anatomy contacting portion defining asubstantially point contact.

In some embodiments, the anatomy facing side of the patient-matchedsurgical instrument includes areas of relatively greater contour andareas of relatively lower contour, wherein a concentration of theplurality of anatomy contacting portions is higher in the areas ofrelatively greater contour than in the areas of relatively lowercontour.

In some embodiments, the anatomy facing side of the patient-matchedsurgical instrument includes areas of relatively greater contour andareas of relatively lower contour, wherein a concentration of theplurality of anatomy contacting portions is lower in the areas ofrelatively greater contour than in the areas of relatively lowercontour.

In some embodiments, at least one of the plurality of anatomy contactingportions extends along a periphery of the anatomy facing side.

In some embodiments, the patient-matched surgical instrument is a tibialcutting guide comprising a medial paddle including at least one of theanatomy contacting portions and a lateral paddle including at least oneof the anatomy contacting portions.

In some embodiments, there is further provided a guide extending throughthe patient-matched surgical instrument.

In some embodiments, the guide is a through slot including at least oneplanar surface.

In some embodiments, there is provided a patient-matched surgicalinstrument matched to the anatomy of a particular patient, comprising:an anatomy facing side; wherein the anatomy facing side includes aplurality of discrete, physically separate anatomy contacting portions,the plurality of anatomy contacting portions configured to match anatomyof the particular patient; wherein the anatomy facing side includes aplurality of discrete, physically separate recessed portions, whereinthe plurality of recessed portions are recessed relative to parts of theanatomy contacting portions proximate the plurality of recessedportions; and wherein the plurality of anatomy contacting portionsdefine a first total area of the anatomy facing side and wherein theplurality of recessed portions define a second total area of the anatomyfacing side; wherein the second total area is greater than the firsttotal area.

In some embodiments, the patient-matched surgical instrument is afemoral cutting guide, wherein the anatomy facing side includes apatella-femoral groove portion, an intercondylar notch portion, a medialcondyle portion, and a lateral condyle portion; wherein the plurality ofanatomy contacting portions comprise at least one anatomy contactingportion proximate the patella-femoral groove portion, at least oneanatomy contacting portion proximate the intercondylar notch portion, atleast one anatomy contacting portion proximate the medial condyleportion, and at least one anatomy contacting portion proximate thelateral condyle portion.

In some embodiments, a total area of the anatomy contacting portionsproximate the patella-femoral groove portion and the intercondylar notchportion is greater than a total area of the anatomy contacting portionsproximate the medial condyle portion and the lateral condyle portion.

In some embodiments, the anatomy facing side of the patient-matchedsurgical instrument includes areas of relatively greater contour andareas of relatively lower contour, wherein a concentration of theplurality of anatomy contacting portions is lower in the areas ofrelatively greater contour than in the areas of relatively lowercontour.

In some embodiments, the anatomy facing side of the patient-matchedsurgical instrument includes areas of relatively greater contour andareas of relatively lower contour, wherein a concentration of theplurality of anatomy contacting portions is higher in the areas ofrelatively greater contour than in the areas of relatively lowercontour.

In some embodiments, there is provided a patient-matched surgicalinstrument matched to the anatomy of a particular patient, comprising:an anatomy facing side; wherein the anatomy facing side includes aplurality of discrete, physically separate anatomy contacting portions,the plurality of anatomy contacting portions configured to match theanatomy of the particular patient; wherein the anatomy facing sideincludes a plurality of discrete, physically separate recessed portions,wherein the plurality of recessed portions are recessed relative toparts of the anatomy contacting portions proximate the plurality ofrecessed portions; wherein the plurality of anatomy contacting portionsare at least one of: non-uniform in distribution; non-uniform in shape;or non-uniform in surface area; and wherein the plurality of anatomycontacting portions define a first total area of the anatomy facing sideand wherein the plurality of recessed portions defines a second totalarea of the anatomy facing side; wherein the second total area isgreater than the first total area.

In some embodiments, there is provided a method for making apatient-matched surgical guide matched to the anatomy of a particularpatient, comprising: receiving data concerning the anatomy of aparticular patient; designing a three-dimensional computer model of theanatomy of the particular patient from the received data; wherein thethree-dimensional computer model includes at least one contact portion;positioning a mesh relative to the three-dimensional computer model todefine at least one non-anatomy contacting portion; designing thepatient-matched surgical guide to match the at least one contact portionand to include a recess avoiding the at least one non-anatomy contactingportion; and manufacturing the designed patient-matched surgical guide.

In some embodiments, positioning the mesh relative to thethree-dimensional computer model comprises positioning the mesh on thethree-dimensional computer model.

In some embodiments, designing the patient-matched surgical guidecomprises intersecting a blank of a surgical guide onto thethree-dimensional computer model and the mesh.

In some embodiments, the method for making the patient-matched surgicalguide further comprises creating an expanded mesh structure from themesh positioned relative to the three-dimensional computer model.

In some embodiments, positioning the mesh relative to thethree-dimensional computer model comprises positioning a first meshrelative to an anterior portion of a three-dimensional computer model ofa distal femur and positioning a second mesh relative to a distalportion of the three-dimensional computer model of the distal femur.

In some embodiments, there is provided a method of designing a surgicalinstrument matched to a particular anatomic structure, wherein thesurgical instrument comprises an anatomy facing side including at leastone anatomy contacting portion and at least one recessed portion that isrecessed relative to parts of the at least one anatomy contactingportion proximate the at least one recessed portion, the methodcomprising: accessing a three-dimensional computer model of the anatomicstructure, the three-dimensional computer model of the anatomicstructure including at least one portion corresponding to the at leastone anatomy contacting portion of the surgical instrument; using acomputer comprising a processor, modifying the three-dimensionalcomputer model of the anatomic structure to create a modifiedthree-dimensional computer model including at least one portioncorresponding to the at least one recessed portion of the surgicalinstrument; and using the modified three-dimensional computer model ofthe anatomic structure to modify a computer model of an instrument blankto correspond to the surgical instrument.

In some embodiments, modifying the three-dimensional computer model ofthe anatomic structure comprises creating a raised portion on thethree-dimensional computer model of the anatomic structure.

In some embodiments, modifying the three-dimensional computer model ofthe anatomic structure comprises positioning a mesh relative to thethree dimensional computer model of the anatomic structure.

In some embodiments, there is further provided the step of creating anexpanded mesh from the mesh.

In some embodiments, positioning the mesh comprises positioning a firstmesh relative to an anterior portion of the three-dimensional computermodel of the anatomic structure and positioning a second mesh relativeto a distal portion of the three-dimensional computer model of theanatomic structure, wherein the three dimensional computer model is amodel of a distal femur.

In some embodiments, positioning the mesh comprises wrapping the mesharound a portion of the three dimensional computer model of the anatomicstructure.

In some embodiments, positioning the mesh comprises positioning a meshhaving a uniform grid pattern.

In some embodiments, accessing the three-dimensional computer model ofthe anatomic structure comprises accessing a three-dimensional computermodel of an anatomic structure of a particular patient.

In some embodiments, using the modified three-dimensional computer modelof the anatomic structure to modify the computer model of the instrumentblank comprises merging the computer model of the instrument blank withthe modified three-dimensional computer model of the anatomic structure.

In some embodiments, using the modified three-dimensional computer modelof the anatomic structure to modify the computer model of the instrumentblank further comprises subtracting an intersecting volume of themodified three-dimensional computer model of the anatomic structure froma volume of the computer model of the instrument blank.

In some embodiments, there is further provided the step of manufacturingthe surgical instrument.

In some embodiments, there is further provided the step of outputtingthe modified computer model of the instrument blank to a deviceconfigured to manufacture the surgical instrument.

In some embodiments, modifying the computer model of the instrumentblank comprises removing portions from a computer model of an oversizedinstrument blank.

In some embodiments, modifying the computer model of the instrumentblank to correspond to the surgical instrument comprises modifying thecomputer model of the instrument blank to correspond to a surgicalinstrument comprising a plurality of discrete, physically separateanatomy contacting portions, wherein the plurality of anatomy contactingportions are at least one of: (i) non-uniform in distribution; (ii)non-uniform in shape; or (iii) non-uniform in surface area.

In some embodiments, modifying the computer model of the instrumentblank to correspond to the surgical instrument comprises modifying thecomputer model of the instrument blank to correspond to a surgicalinstrument wherein the at least one anatomy contacting portion defines afirst total area of the anatomy facing side and wherein the at least onerecessed portion defines a second total area of the anatomy facing side;wherein the second total area is greater than the first total area.

In some embodiments, there is provided a method of designing a surgicalinstrument matched to a particular anatomic structure, wherein thesurgical instrument comprises an anatomy facing side including at leastone anatomy contacting portion and at least one recessed portion that isrecessed relative to parts of the at least one anatomy contactingportion proximate the at least one recessed portion, the methodcomprising: accessing a three-dimensional computer model of the anatomicstructure, the three-dimensional computer model of the anatomicstructure including at least one portion corresponding to the at leastone anatomy contacting portion of the surgical instrument; using acomputer comprising a processor, modifying the three-dimensionalcomputer model of the anatomic structure to create a modifiedthree-dimensional computer model including at least one portioncorresponding to the at least one recessed portion of the surgicalinstrument, wherein modifying the three-dimensional computer model ofthe anatomic structure comprises positioning a mesh relative to thethree dimensional computer model of the anatomic structure; and usingthe modified three-dimensional computer model of the anatomic structureto modify a computer model of an instrument blank to correspond to thesurgical instrument.

In some embodiments, positioning the mesh comprises positioning a firstmesh relative to an anterior portion of the three-dimensional computermodel of the anatomic structure and positioning a second mesh relativeto a distal portion of the three-dimensional computer model of theanatomic structure, wherein the three dimensional computer model is amodel of a distal femur.

In some embodiments, positioning the mesh comprises wrapping the mesharound a portion of the three dimensional computer model of the anatomicstructure.

In some embodiments, positioning the mesh comprises positioning a meshhaving a uniform grid pattern.

In some embodiments, there is provided a method of designing a surgicalinstrument matched to a particular anatomic structure, wherein thesurgical instrument comprises an anatomy facing side including at leastone anatomy contacting portion and at least one recessed portion that isrecessed relative to parts of the at least one anatomy contactingportion proximate the at least one recessed portion, the methodcomprising: accessing a three-dimensional computer model of the anatomicstructure, the three-dimensional computer model of the anatomicstructure including at least one portion corresponding to the at leastone anatomy contacting portion of the surgical instrument; using acomputer comprising a processor, modifying the three-dimensionalcomputer model of the anatomic structure to create a modifiedthree-dimensional computer model including at least one portioncorresponding to the at least one recessed portion of the surgicalinstrument, wherein modifying the three-dimensional computer model ofthe anatomic structure comprises positioning a mesh relative to thethree dimensional computer model of the anatomic structure; using themodified three-dimensional computer model of the anatomic structure tomodify a computer model of an instrument blank to correspond to thesurgical instrument by: merging the computer model of the instrumentblank with the modified three-dimensional computer model of the anatomicstructure; and subtracting an intersecting volume of the modifiedthree-dimensional computer model of the anatomic structure from a volumeof the computer model of the instrument blank; and outputting themodified computer model of the instrument blank to a device configuredto manufacture the surgical instrument.

Further areas of applicability of the inventions and their embodimentsdescribed herein will become apparent from the detailed descriptionprovided hereinafter. It should be understood that the writtendescription and accompanying drawings in this document, whileillustrating particular embodiments of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe inventions.

BRIEF DESCRIPTION OF FIGURES

FIGS. 1-8 illustrate an embodiment of a patient-matched surgicalinstrument in the form of a femoral cutting guide.

FIGS. 9-14 illustrate an embodiment of a patient-matched surgicalinstrument in the form of a tibial cutting guide.

FIGS. 15-16 illustrate an embodiment of a patient-matched surgicalinstrument in the form of a tibial cutting guide.

FIGS. 17A-17C illustrate additional embodiments of patient-matchedsurgical instruments.

FIGS. 18A-B and 19 illustrate embodiments of a patient-matched surgicalinstrument in the form of femoral cutting guides, each havinganatomy-contacting portions that vary in contact area, shape, and/ordistribution.

FIG. 20 illustrates potential points of contact between a femur bone anda patient-matched surgical instrument (not shown) according to anotherembodiment.

FIGS. 21 and 22 illustrate two embodiments of patient-matched surgicalinstruments in the form of femoral cutting guides, each havinganatomy-contacting portions in the shape of substantial line segments.

FIGS. 23 and 24 illustrate two embodiments of patient-matched surgicalinstruments in the form of femoral cutting guides, each havinganatomy-contacting portions located generally around the peripheralareas of the instrument and/or guide structures of the instrument.

FIG. 25 illustrates a patient-matched surgical instrument including apliant material.

FIG. 26 illustrates a method step of creating a three-dimensionalpatient-specific anatomic model according to one embodiment.

FIG. 27A illustrates an embodiment of a method step of creating andapplying a first mesh structure to a first portion of a first anatomicmodel; FIG. 27B illustrates an embodiment of a method step of creatingand applying a second mesh structure to a second portion of the firstanatomic model; FIG. 27C illustrates an embodiment of a method step ofcreating a first mesh structure and a second mesh structure, andapplying the first and second mesh structures to first and secondportions of a first anatomic model, respectively; and FIG. 27Dillustrates the method step of FIG. 27C further including the methodstep of determining an intersection of a surgical instrument blank withrespect to a first anatomic model.

FIGS. 28-31 illustrate an embodiment of a method step of performing oneor more sweep functions to a mesh structure, after said mesh structureis applied to an outer portion of a first anatomic model, to create amodified first anatomic model.

FIGS. 32A and 33A illustrate a surgical instrument blank for use with amodified first anatomic model according to some embodiments, havingsuperimposed thereon a virtual intersection with the first modifiedanatomic model.

FIGS. 32B and 33B illustrate the surgical instrument blank of FIG. 32A,having superimposed thereon a first mesh structure applied to a firstportion of a first anatomic model.

FIGS. 32C and 33C illustrate the surgical instrument blank of FIG. 32A,having superimposed thereon a second mesh structure applied to a secondportion of a first anatomic model.

FIGS. 34 and 35 illustrate an embodiment of a method step of merging asurgical instrument blank with a modified first anatomic model, whichmay, in some embodiments, be followed by subtracting the modified firstanatomic model from the surgical instrument blank to define apatient-matched surgical instrument.

FIGS. 36-38 show another embodiment of a modified first anatomic model.

FIG. 39 illustrates an embodiment of a method step of merging a surgicalinstrument blank with the modified first anatomic model shown in FIGS.36-38, and then subtracting the intersecting portions of the modifiedfirst anatomic model from the surgical instrument blank.

FIG. 40 illustrates an embodiment of a method step of merging first andsecond surgical instrument blanks with modified first and secondanatomic models, respectively.

FIG. 41 illustrates an embodiment of modified first and second anatomicmodels, wherein one or more sweep functions are executed for meshstructures applied to first and second anatomic models.

FIG. 42A illustrates a second mesh structure created and applied to asecond portion of a first anatomic model according to some embodiments;FIG. 42B illustrates a first mesh structure created and applied to afirst portion of a first anatomic model according to some embodiments.

FIG. 43A illustrates a second mesh structure created and applied to afirst portion of a second anatomic model according to some embodiments;FIG. 43B illustrates a first mesh structure created and applied to asecond portion of a second anatomic model according to some embodiments.

FIGS. 44 and 45 illustrate a method step of merging a second surgicalinstrument blank with a modified second anatomic model.

FIGS. 46 and 47 illustrate additional embodiments of patient-matchedsurgical instruments.

FIG. 48 schematically illustrates one embodiment of a method ofdesigning and manufacturing a surgical instrument.

DETAILED DESCRIPTION OF DRAWINGS

The following description of the drawings is merely exemplary in natureand is in no way intended to limit the invention, its application, oruses.

FIGS. 1-8 illustrate a first embodiment of a patient-matched surgicalinstrument, which, in this embodiment, is a femoral cutting guide 10.The femoral cutting guide 10 has an anatomy facing side 12 including ananterior portion 14 that is configured to face a patello-femoral grooveand anterior cortex region of a distal femur. The instrument furthercomprises two condylar portions (a medial condyle portion 16 and alateral condyle portion 18) separated by an intercondylar notch 20, inwhich the condylar portions are configured to face distal condylarportions of a patient's femur. The patient-matched femoral cutting guide10 of FIGS. 1-8 also includes a through slot 22 for guiding a cuttinginstrument such as a saw blade. The cutting guide 10 additionallyincludes a plurality of bosses 24 having apertures 26 extendingtherethrough to guide one or more stabilizing fasteners or locatingpins, which may or may not be pre-drilled using the apertures. Forinstance, apertures 26 may be located on the condylar portions anddetermine a rotation or peg hole location of an implanted femoralprosthetic component. The through slot 22 and apertures 26 areoccasionally referred to herein as “guide structures,” although thatterm may also encompass structures other than just apertures and slots.In some embodiments, the guide structures are optional and are notnecessarily integrally incorporated into the patient-matched instrument.In some embodiments, guides, bosses, and other structure may be includedin non-patient-matched, standardized modular components that are laterconnected to or otherwise associated with the patient-matchedinstrument.

The femoral cutting guide of FIGS. 1-8 includes a plurality of discrete,physically separate anatomy contacting portions 28 on the anatomy facingside 12. The anatomy contacting portions 28 are configured to match theanatomy of a particular patient, and, in some embodiments, may becustomized to a particular patient based on pre-operatively obtainedimaging data of that patient.

In other embodiments, the patient-matched surgical instrument and itsanatomy contacting portions are matched to a particular patient by usingthe pre-operatively obtained imaging data of that patient to select apatient-matched surgical instrument from a set of pre-determinedinstruments. For instance, in one embodiment, the set of pre-determinedinstruments includes hundreds (e.g. 1200) of pre-determined instruments,such as CAD computer models of instruments, among which automatedsoftware or other automated or non-automated functionality may be usedto select one instrument from the set that best fits the particularpatient, thereby matching the selected surgical instrument to theanatomy of the particular patient.

In the embodiment of FIGS. 1-8, the anatomy contacting portions 28define substantially linear contacts (in this particular embodiment,splines). Other substantially linear contacts may be utilizedadditionally or alternatively, including, but not limited to straightline segments, arcuate line segments, or curvilinear segments such asshown in some of the later described embodiments. Other types of anatomycontacting portions are substantial point contacts and area contacts.Non-limiting examples of anatomy contacting portions include teeth,ridges, undulations, serrations, spines, platforms, posts, nodules,tubes, pads, shapes specific to corresponding anatomical features orportions of such anatomical features, and/or various combinationsthereof. The anatomy contacting portions may be spaced homogenously andevenly across an anatomy-facing side, or the anatomy contacting portionsmay be selected and distributed in random, non-random, pre-determined,optimized, or other fashion across the anatomy facing side. In someembodiments, the anatomy-contacting portions may create substantial linecontacts with areas of bone and/or cartilage, but, in other embodiments,may contact bone, cartilage, and/or other anatomy in other manners(including point and area contacts). In some embodiments, the locationsof the anatomy contacting portions may be determined using a randomnumber generator or similar functionality.

The geometry of portions of the anatomy facing side of the instrumentthat do not contact bone or cartilage (the “recessed portions”) mayvary. In the example of FIG. 1, the recessed portions 30 are a series offlutes or channels extending between the anatomy contacting portions 28.These flutes or channels are shown to be generally rectangular ortrapezoidal in cross-section, but any cross-section may be used invarious embodiments. For example, as shown in FIGS. 9-14, rounded orpartially cylindrically shaped flutes or channels 32 may alternativelyprovide clearance regions where the instrument is not designed tocontact the patient's anatomy. In some instances, the recessed portionsmay be partially or wholly made up of apertures extending through thesurgical instrument.

In some embodiments, such as the embodiment shown in FIG. 1, the totalarea of the recessed portions 30 of the anatomy facing side 12 of theinstrument is greater than the total surface area of the anatomycontacting portions 28 of the anatomy facing side 12. In other words, inat least this particular embodiment, the anatomy contacting portions 28make up only a small portion of the anatomy facing side 12 of thefemoral cutting guide 10.

As shown in FIG. 25, in some embodiments, at least some of the recessedportions 34 may be provided with a pliant material 26 that partially orcompletely fills one or more of the “gaps” between the anatomycontacting portions and the recessed portions.

Returning to the embodiment of FIGS. 1-8, the anatomy contactingportions 28 may extend generally parallel across the anatomy facing side12 of the femoral cutting guide 10. In other embodiments, however, theanatomy contacting portions are non-parallel and/or are provided at anangle with respect to one another (perpendicular, acute, or obtuseangles). Additionally, the anatomy contacting portions may bediscontinuous so as to create dotted line or partial line or curvesegment contacts between the instrument and the patient's uniqueanatomy.

In some embodiments, the anatomy contacting portions may be non-uniformin distribution, non-uniform in shape, and/or non-uniform in contactarea. In some embodiments, such non-uniformities may relate to thedegree of contour in the particular region of the patient-matchedinstrument.

For example, FIG. 18A illustrates a femoral cutting guide 38 thatincludes anatomy contacting portions that define area contacts 40 (here,substantially rectangular shaped contacts) as well as anatomy contactingportions that define substantially linear contacts 42. In thisparticular embodiment, in less contoured areas of the anatomy facingside 44, the anatomy contacting portions have a larger contact area thananatomy contacting portions in areas having a greater contour. Forexample, the area proximate the femoral condyles is generally lesscontoured than the areas proximate the patella-femoral groove andintercondylar notch. Thus, area contacts 40 generally have a larger areathan substantially linear contacts 42, which, in some embodiments, maynot be “area” contacts at all and be splines, ridges or other structuresthat contact the anatomy along a discrete line. In some embodiments, theanatomy contacting portions may also vary in height depending on thecontour of the surgical instrument. For example, the femoral condylesstand proud whereas the intercondylar notch is more recessed. Thus,anatomy contacting portions proximate the femoral condyles may begenerally shorter than anatomy contacting portions proximate theintercondylar notch. In such embodiments, the substantially linearcontact portions are narrow and tall, and thus approximate adiscontinuous ridge that is dimensioned to contact a patient's anatomyalong the deepest portion of the trochlear groove to provideinternal/external rotational stability as well as stabilize theinstrument with respect to the patient's femur in a varus/valgus aspect.(In other embodiments, an anatomy contacting portion shaped like acontinuous ridge or line segment may be provided in this area.)

While contrary to the above teachings, it is also envisioned that largercontacting portions may be provided in areas with greater contouring(such as the intercondylar notch or trochlear groove), and smallercontacting portions may be provided in areas with less contouring (suchas the femoral condyles). As one example, the embodiment shown in FIG.18B includes a horseshoe-shaped contacting portion 46 proximate theintercondylar notch, and a large contacting portion 48 proximate thetrochlear groove. In contrast, smaller contacting portions 50 areprovided proximate the condyles where there is less contouring.

FIG. 19 illustrates another embodiment of a patient-matched surgicalinstrument that includes anatomy contacting portions that vary in shapedepending upon the contour of the instrument. In this embodiment,contacting portions 52 and 54 are generally rectangular (but may vary insize and/or height), whereas contacting portions 56 are generallycone-shaped. The different shaped contacting portions provide fordifferent types of contact between the surgical instrument and apatient's anatomy. For example, rectangular contacting portions 52provide for increased area contact with the patient's anatomy, narrowcontacting portions 54 provide line contact (or substantial linecontact) to nest within the trochlear groove, and cone-shaped contactingportions 56 provide for point contact (or substantially point contact)with the patient's anatomy. The shapes of the anatomy contactingportions may be selected to provide for a particular type of contactwith particular portions of the patient's anatomy. For example, narrowrectangular and/or wedge-shaped contacting portions (such as contactingportions 54) may be selected for mating with the trochlear groove of thepatient's distal femur. In contrast, wider rectangular contactingportions 52 may be selected to provide maximum area contact against thefemoral condyles, albeit in a discrete region or regions of the femoralcondyles. Cone-shaped contacting portions 56 may be selected when it isdesired to reduce the amount of segmentation of image data required bythe CAD modeling functionality.

Additionally, FIG. 19 illustrates that the distribution (or density) ofthe anatomy contacting portions may vary depending on the contour of theinstrument. In FIG. 19, a larger number of anatomy contacting portionsare concentrated in areas of the instrument having greater contour.Thus, contacting portions 54 and 56 are positioned proximate to thepatello-femoral groove and intercondylar notch portions of theinstrument (areas having greater contour), whereas contacting portions52 are provided proximate to the femoral condyle portions (an areahaving relatively less contour). There are only two contacting portions52, whereas there are more than two contacting portions 54 and 56.

FIG. 20 shows several arrows conceptually illustrating substantiallypoint contacts between a patient's anatomy and contacting portions ofanother embodiment of a surgical instrument. In the embodiment of FIG.20, the arrows indicate that there are generally more points of contactproximate to areas of the patient's anatomy having more contour.

While contrary to the above teachings, it is also envisioned that alarger number of anatomy contacting portions may be concentrated inareas of the instrument having less contour. Thus, areas proximate tothe femoral condyle portions of the instrument may be provided with moreanatomy contacting portions than in areas proximate to the intercondylarnotch portion of the instrument. In this way, the anatomy contactingportions are concentrated in areas where segmentation error may be lesslikely to exist (at least in some embodiments)—the larger, lesscontoured areas—rather than areas with a greater amount of contour.Since conventional patient scans (e.g., MRI) comprise a compilation of2D image slices that are spaced by intervals of approximately 2-4 mm,interpolation algorithms or other methods are used to approximateanatomical geometries between the image data slices. By focusing contactportions in areas where there is less change in geometry between 2Dimage slices, instrument fit may be improved.

FIGS. 21 and 22 illustrate embodiments where the anatomy contactingportions are substantially linear contacts. The substantially linearcontacts may be relatively straight (at least in two dimensions), or mayhave at least one curved segment. Thus, in the embodiment shown in FIG.21, there is provided one “S-shaped” contacting portion 58 that providesgreater contact with the patient's anatomy and may also increaseinternal and external rotational stability. As shown, there may also beother contacting portions 60 that are more linear than the S-shapedportion 58, contacting portions 60 being located proximate the condylarportions of the instrument. If desired, these two contacting portions 60may be shaped to generally follow the apex contour of the condyles.

The anatomy contacting portions 58 and 60 shown in FIG. 21 are discreetin that they have a first end and a second end that are not connected toeach other. In the embodiment shown in FIG. 22, the anatomy contactingportions connect with each other. Thus, there is provided a“waffle-shaped” contacting portion 62 including multiple line segments64 connected to one another, and “ring-shaped” contacting portions 66comprising a single curvilinear line segment connected at its ends. Ifdesired, the ring-shaped contacting portions 66 may be located proximatethe condylar portions of the instrument, such that the patient'scondyles “nest” within the ring-shaped contacting portions 66. Any othertype of hatch or grid pattern comprising multiple line segments, and/oroval or annulus-shaped line segments are also within the scope of thisinvention.

The anatomy contacting portions shown and described in FIGS. 21 and 22may match to recessed portions of the patient's anatomy (such as thetrochlear groove or intercondylar notch), but may also match portions ofthe anatomy that sit proud in relation to other anatomy (such as themedial and lateral distal condyles). The anatomy contacting portions maymatch either articulating or non-articulating portions of the patient'sanatomy. If desired, one or more discrete substantially point contactportions (such as contacting portions 56 in FIG. 19) may be providedalong with the line-segment contacting portions shown in FIGS. 21 and22.

FIGS. 23 and 24 illustrate embodiments where the anatomy contactingportions 68 are more heavily concentrated in peripheral areas 70 of theinstrument and/or guide structures (such as but not limited to apertures72 to receive fixation pins, or through slots 74 to receive cuttinginstruments). It is not necessary in all embodiments for the anatomycontacting portions to extend completely around the perimeter of thesurgical instrument. Rather, the contacting portions may only extendaround a portion of the perimeter. Additionally, it is not necessary forthe anatomy contacting portions to extend completely around the guidestructures (the contacting portions may only be located on the top ofthe through-slot, for example), or for the contacting portions to extendaround each of the guide structures (only some guide structures may beprovided with contacting portions).

Locating the anatomy contacting portions in such peripheral areas mayincrease stability of the instrument when the instrument is placed onthe patient's anatomy, or when the surgeon uses the guide structures(for example, when the through-slot receives a cutting instrument forcutting bone). In the embodiment shown in FIG. 23, the anatomycontacting portions 68 are discontinuous ridges that are shaped likerectangles or wedges. (Of course, other shapes may be provided, such ascylinders, cones, spheres, pyramids, or any other shape describedherein.) In FIG. 24, there is provided a single almost entirelycontinuous anatomy contacting portion 68 that extends around theperimeter 70 of the instrument. If desired, additional anatomycontacting portions may be placed in central regions of thepatient-matched instrument.

Additionally, FIG. 24 shows that in certain embodiments, portions (e.g.portion 76) of the surgical instrument may be “hollow” such that theyare defined by a sidewall 78, the top edges of which define thecontacting portions 68 of the instrument. In FIG. 24 the bottom half ofthe surgical instrument is hollow, whereas the top half is non-hollow.In the bottom half, the anatomy contacting portions 68 extend into thesurgical instrument and define the sidewalls 78 of the hollow bottomhalf. Thus, the bottom half of the instrument resembles a cup, where thelip of the cup comprises the anatomy contacting portions 68. In otherembodiments, the entire surgical instrument may be hollow.

Any or all of the anatomy contacting portions described herein may betextured to improve the overall stability of the patient-matchedinstrument. For example, the texturing may include serration, points,cross-hatch, grooves, ridges, bumps, or barbs that increase the frictionbetween the patient's anatomy and the patient-matched instrument. Incertain embodiments the texturing at least slightly penetrates thepatient's soft tissue or other anatomy, which may, in some embodiments,compensate for segmentation errors that may occur in regions havinggreater amounts of soft tissue. In some embodiments, it may be desirableto locate the textured portions proximate the perimeter of theinstrument and/or guide structures. If desired, central regions of thecondylar portions and anterior portion (where more hard tissue such asbone is located) may remain smooth for best fit.

FIG. 25 illustrates an embodiment of a patient matched surgicalinstrument including pliant material 36 located in a recessed (ornon-contacting) portion 34 of the instrument. With at least some of theembodiments described herein, when surgical instruments having anatomycontacting portions are placed against the patient's anatomy a gap orspace may be left between the anatomy and the recessed portions (e.g. 34in FIG. 25) of the instrument that do not contact the anatomy. The gapsmay give the perception of a non-conforming fit, and moreover, the gapsmight contribute to instability of the instrument. Thus, at least onepliant portion may be provided within a recessed portion of the surgicalinstrument. In some embodiments, the pliant portion completely fills therespective recessed area, but in other embodiments, the pliant portiononly fills a portion of the recessed area (e.g. as shown in FIG. 25).The pliant portion may comprise a silicone material, polymer film,gauze, putty, or dough that presses against and at least partially takeson the shape of the patient's anatomy, filling any gaps that mightotherwise be present between the discrete anatomy contacting portions.The pliant portions, together with the anatomy contacting portions, mayin some embodiments approximate a continuous mirror-image surface of thepatient's anatomy. Thus, the pliant portions provide the benefits of acontinuous mirror-image surface (such as stability) to surgicalinstruments that only have discontinuous anatomy contacting portions.The pliant portions may be coupled to the surgical instrument eitherbefore or during surgery, using adhesive, mechanical fasteners, welding,or the like. Alternatively, the pliant portions may simply be placedwithin the recessed portions without any structure or substance tocouple the pliant portion to the instrument. In some embodiments, apliant material such as a polymer may be injected into the recesses ofthe instrument after manufacture.

Various embodiments of patient-matched surgical instruments may featuredifferent fill depths of a pliant material in the recessed portions. Forinstance, in one embodiment, the pliant material may fill the recessedportions up to the level of the surrounding anatomy contacting portions;however, in other embodiments, the pliant material may be below thelevel of the surrounding anatomy contacting portions or above the levelof the surrounding anatomy contacting portions. In embodiments where thefill level of the pliant material is below the level of the surroundinganatomy contacting portions, it may facilitate visualizing the fit ofthe instrument on the anatomy. In some embodiments where the pliantmaterial is level with surrounding anatomy contacting portions, thepliant material may also contact the anatomy and add at least somedegree of stability to the instrument/anatomy interaction. In someembodiments where the fill level of the pliant material is above thelevel of the surrounding anatomy contacting portions, pressing theinstrument onto the anatomy may cause the pliant material to expand,filling in the recessed portions. In at least some these embodiments,such as the embodiment where the pliant material is above the level ofthe surrounding anatomy contacting portions, the pliant material may beheld in place by pinning the instrument to the anatomy. In this andother embodiments, the pliant material may provide increased frictionbetween the instrument and anatomy, such that the position andorientation of the instrument on the anatomy is further maintainedduring the pinning process.

In some embodiments, the pliant material may be more localized(partially or entirely) in areas configured for contact with bonyanatomy (e.g. relatively superior, anterior portions of the anatomyfacing side of a femoral cutting guide) and the anatomy contactingportions may be more localized (partially or entirely) in areasconfigured for contact with cartilaginous anatomy (e.g. condylar andother areas of a femoral cutting guide). In other embodiments, otherdistributions (either regular or irregular) of pliant material andanatomy contacting portions are possible.

FIGS. 9-14 illustrate an embodiment of a patient-matched surgicalinstrument, in this instance a tibial cutting guide 80. The tibial guide80 shown includes a guide 82 for directing a saw blade (or, in otherembodiments, for directing other types of surgical tools such as amilling bit, osteotome, drill, wire, or pin). Although not shown, insome embodiments, the surgical instrument may have features forattaching modules for directing surgical tools rather than incorporatinga surgical guide directly into the tool. The tibial cutting guide 80shown in FIGS. 9-14 also includes several apertures 84 for receivingpins or other fasteners for securing the instrument to the patient.

The guide portion 82 of the tibial cutting guide 80 shown in FIGS. 9-14is partially cantilevered off of other portions, and may be configuredto contact a patient's anatomy to some degree or may be configured toclear the patient's anatomy relative to anatomy contacting portions ofthe instrument. In the particular embodiment shown, as best seen in FIG.11, the cantilevered portion of guide 82 is not configured to directlycontact the patient's anatomy, whereas central portions of the guide 82do include anatomy contacting portions 86 on the anatomy facing side ofthe tibial cutting guide 80.

In the embodiment of FIGS. 9-14, the tibial cutting guide 80 alsoincludes two paddles 88, portions of which are for contacting superiorportions of a proximal tibia. In the particular embodiment shown, thetwo paddles 88 are provided for contacting points on medial and lateralarticular zones of a proximal tibial plateau, adjacent the tibialeminence, although, in other embodiments, the paddles may be designed tocontact other portions of the anatomy. As shown in FIG. 9, indicia 90may be provided on the instrument for indicating relative mechanicalaxis alignment, size, patient data, data relative to the surgery to beperformed, data regarding an orientation of the instrument, or surgeondata, without limitation.

The tibial cutting guide 80 of FIGS. 9-14 is similar to the femoralcutting guide of FIGS. 1-8 in that it employs anatomy contactingportions (here ridges 86) on the anatomy facing side of the instrument.The anatomy contacting portions 86 shown are configured to create splinecontacts between the instrument and the patient's tibial bone and/orcartilage, although many other types, arrangements and distributions ofanatomy contacting portions are also possible. An anterior portion 92 ofthe instrument is configured to partially engage cortical bone adjacentthe anterior cortex and medial ⅓ of the tibial tubercle. The splinecontacts shown are generally evenly distributed about the anteriorportion 92 and distal paddle portions 88 of the instrument; however, asdescribed above, the anatomy contacting portions may be randomized, ordistributed in some other predetermined non-homogeneous fashion.Moreover, as previously stated, the number, location, orientation, size,width, profile, continuity, and shape of each anatomy contacting portionmay be varied as needed to optimize interaction with a particularpatient's unique anatomy or for other purposes.

FIGS. 15-16 illustrate another embodiment of a patient matched tibialcutting guide 94 in which the anatomy contacting portions are severalsubstantially point contacts 96. As shown, each point contact 96includes a pad at its peak for contact with a point on the patient'sanatomy. In some embodiments, the pad may be substantially square, andmay range in size from 0.1 to 10 mm square (measured along a side of thesquare) in some embodiments, from 0.5 to 5 mm square in someembodiments, and from 1 to 3 mm square in some embodiments. FIGS. 46 and47 schematically show other patient-matched instruments (femoral cuttingguides 98 and 100 respectively) having different sized pads (102 and 104respectively). In some embodiments, the pads are not square shaped, andmay take on other shapes such as circles, triangles, rectangles, otherpolygons, or other shapes. In some embodiments, the substantially pointcontacts are not pads, but contact the anatomy at only one or a verylimited number of points. For instance, in some embodiments, eachsubstantially point contact may have a rounded apex or sharp apex (asopposed to the flat apexes shown) that only contacts the anatomy at asingle point or very small number of points. In some embodiments, eachsubstantially point contact may define multiple peaks that each contactsthe anatomy in a limited number or only a single point.

FIGS. 17A-17C illustrate additional embodiments of patient matchedsurgical instruments. FIG. 17A illustrates a tibial cutting guide 106similar to that shown in FIGS. 15-16 in that anatomy contacting portions108 are provided on both the paddles 110 and the anterior portion 112 asa plurality of substantial point contacts (which, as mentioned earlier,make take on a variety of forms, including, but not limited to, a seriesof bumps, domes, spikes, cones, cylinders, polyhedrons (e.g., triangles,diamonds, pyramids), or other geometries or structures which wouldcreate substantially point contacts between the instrument and apatient's anatomy). As shown in FIG. 17A, however, central areas 114 ofthe anterior portion 112 are devoid of/have a lower concentration ofanatomy contacting portions 108, whereas a larger concentration ofanatomy contacting portions 108 is provided on a periphery or perimeterof the anterior portion 112 and areas of the instrument adjacent a guidestructure 116. FIGS. 17B and 17C illustrate other embodiments of acustomized surgical instrument for a tibia—each comprising a firstregion having one type of anatomy contacting portions, and a secondregion comprising another type of anatomy contacting portions. Inparticular, FIG. 17B shows an embodiment in which paddles of theinstrument include dimples 118 configured for substantially pointcontact with a patient's unique anatomy, and the anterior portion of thecustomized surgical instrument includes raised splines 120 configured topresent spline/substantial line contacts with respect to the patient'sanatomy. FIG. 17C shows an embodiment in which the anterior portion ofthe patient-matched surgical instrument includes dimples 122 configuredfor providing a series of substantially point contacts with a patient'sunique anatomy, and the paddles of the customized surgical instrumentinclude raised splines 124 configured to present spline/substantiallyline contacts with respect to a patient's anatomy.

FIGS. 26-35 illustrate various method steps associated with the creationof some of the patient-matched surgical instruments shown and describedherein, according to some embodiments. While the method steps are shownand described in conjunction with a patient's distal femur, it should benoted that the various method steps may be applied to any portion of apatient's anatomy, without limitation. In addition, the embodiments ofthe patient-matched surgical instruments discussed above for FIGS. 1-25,and other embodiments of patient-matched surgical instruments within thescope of the present disclosure, do not necessarily have to be createdusing the embodiments of methods illustrated in FIGS. 26-35 and can becreated in a variety of other ways. Moreover, the methods shown anddescribed below may be used to create patient-matched surgicalinstruments other than those shown in FIGS. 1-25.

In general, the non-limiting embodiment illustrated in FIGS. 26-35involves: (1) creating, obtaining or otherwise accessing a digital orother form of a three dimensional model of the patient's anatomy ofinterest; (2) applying one or more mesh or grid overlays onto portionsof the bone model; (3) performing a sweep function that modifies themesh or grid overlay(s) to create a geometric construct that definesareas where the anatomy contacting portions are and areas where theanatomy contacting portions are not on the anatomy facing side of thepatient specific instrument; (4) merging the modified overlay(s) withthe bone model; and (5) applying an oversized blank of the instrument tothe modified bone model to identify portions of the blank for removal(in some embodiments, portions of a virtual blank for removal) such thatpatient-matched anatomy contacting portions are formed or otherwisepresent or created to define a patient-matched instrument. FIG. 48schematically illustrates one embodiment of a method involving accessinga three dimensional anatomic model (1002), modifying the anatomic model(1004), using the modified anatomic model to modify an instrument blank(1006), outputting the modified instrument blank to a manufacturingdevice (1008), and manufacturing the surgical instrument (1010).

FIG. 26 illustrates a method step of creating a first anatomic model 126utilizing 3D imaging data obtained from a patient as conventionallydone, such as by, but not limited to, magnetic resonance imaging, x-ray(including digital x-rays), ultrasound, or other techniques. In someembodiments, non-image based technologies may be use to obtainsufficient data about the 3D structure of the anatomy of interest toallow a patient-matched instrument in accordance with this disclosure tobe created. In some embodiments, the first anatomic model is not acomplete model of the particular portion of the anatomy of interest, butis only a model of certain key or desired anatomical points or portionsof the anatomy of interest. The first anatomic model 126 may beelectronically stored in a computer storage memory and imported into acomputer assisted design (CAD) software package or other types of designsoftware packages.

FIG. 27A illustrates a method step of creating and applying a first meshstructure 128 to a first portion of a first anatomic model 126. In someembodiments, the first mesh structure 128 (either by itself or inconjunction with other mesh structures) defines or at least roughlycorresponds to at least some aspects of the number, position, and/ororientation of the anatomy contacting portions of the patient-matchedinstrument as well as the recessed portions interspersed among thoseanatomy contacting portions. Although the mesh structure 128 shown inFIG. 27A may be characterized as being defined by a square, uniform gridpattern, the mesh structure may have any geometric shape, size,porosity, or density, including a gradient density or porosity. The meshstructure may be evenly distributed, or may be random in nature, orotherwise have a predetermined pattern. Shown in FIG. 27A is oneembodiment of an anterior mesh structure 128 for application to, orprojection onto or “wrapping around” an anterior outer surface of thefirst model 126 shown in FIG. 26 (which here is a distal femur, the“anterior outer surface” being adjacent the trochlear groove, anteriorcortex, and surrounding articular surfaces).

FIG. 27B illustrates a method step of creating and applying a secondmesh structure 130 to a second portion of the first anatomic model 126of FIG. 26. As previously mentioned, the mesh structure may have anygeometric shape, size, porosity, or density, including a gradientdensity or porosity. The mesh structure may be evenly distributed, ormay be random in nature, or otherwise have a predetermined pattern.Shown in FIG. 27B is an embodiment of a distal mesh 130 to be applied toor otherwise projected onto or “wrapped around” one or more inferiorsurfaces of the first model 126 (here, adjacent the condyles andintercondylar notch of the first bone model 126 shown in FIG. 26).

FIG. 27C illustrates a method step of creating a first mesh structure128 and a second mesh structure 130, and applying both the first andsecond mesh structures to first and second portions of the firstanatomic model 126 (e.g. of FIG. 26), respectively. The first and secondmesh structures 128 and 130 may be united as one homogenous meshstructure, or the mesh structures may be kept independent and distinctso that different sweep functions may be applied to each mesh structureto form different anatomy-contacting portion profiles on the differentportions of the first anatomic model 126. As shown in FIG. 27C, the meshstructures 128 and 130 may overlap one another, although, in otherembodiments, they may be designed not to overlap when applied to thefirst anatomic model 126.

FIG. 27D illustrates an embodiment of a method step of determining anintersection of a surgical instrument blank 132 with respect to thefirst anatomic model 126. As shown in FIG. 27D, and will be described inmore detail hereinafter, the surgical instrument blank 132 (which may besized according to an individual patient or “universal” for all patientsizes) is virtually merged with the first anatomic model 126 whichincludes the first and/or second mesh structures 128 and 130 (or othernumbers and combinations of mesh structures in other embodiments). Theintersection between the blank 132 and the first anatomic model 126defines an intersection perimeter 134 (i.e., the border of the interfacebetween the virtually merged blank and first anatomic model). Theintersection perimeter 134 is shown to be superimposed over the firstand second mesh structures 128 and 130 in FIG. 27D. In some embodiments,the mesh structures is designed in such a manner (or the method isotherwise altered) to avoid a separate step of determining intersectionsbetween the blank and the first anatomic model 126.

FIGS. 28-31 illustrate a method step of performing one or more sweepfunctions to the mesh structure(s) to create an expanded mesh structure136. The one or more sweep functions may be executed before or after themesh structures 128 and 130 are applied to the first anatomic model 126.In other embodiments, performing a sweep function is unnecessary and thegeometry of the mesh structure may already include geometries other thansimple lines or grids such that “expanding” on a line grid is notnecessary. In the embodiment illustrated in FIGS. 28-31, after the oneor more sweep functions are executed, the resulting volume of theexpanded mesh structure 136 and the first anatomic model 126 are unitedto create a modified first anatomic model 138. Shown in FIG. 28 is aportion of a modified first anatomic model 138 incorporating the firstanterior mesh structure 128 shown in FIG. 27A and the second distal meshstructure 130 shown in FIG. 27B, after the mesh structures have beenexpanded by one or more sweep functions in CAD software. The resultingvolumes of the first and second expanded mesh structures are shown to beunited with the volume of the first anatomic model 126 shown in FIG. 26.In the embodiment shown in FIG. 28, the indentations left in themodified first anatomic model 138 after the expanded mesh structure hasbeen united with the anatomic model 126 may correspond (at leastpartially) to the locations, sizes, geometries and other aspects of theanatomy contacting portions of the patient-matched surgical instrument.

In some embodiments, the sweep function may be applied to a first meshstructure that is united with the bone model prior to applying the sameor a different sweep function to a second mesh structure for unitingwith the bone model. In other embodiments, the first and second meshstructures may both have the same or different sweep functions appliedand then both be united with the bone model at the same time. It will beapparent to one of skill in the art that other combinations anddifferent orderings of these method steps are possible and within thescope of possible embodiments discussed herein.

It should be noted that while the sweep function applied to the firstand second mesh structures 128 and 130 shown in FIG. 28 include aflattened rectangular cross-section, any cross-sectional geometry may beapplied to mesh structures described herein. For example, a triangular,polygonal, circular, oval, irregular, or other cross-sectional shape orprofile may be applied to the mesh structures to obtain a differentmodified first anatomic model. Moreover, a different sweep function maybe applied to each line, area, region, strut or segment of a meshstructure to obtain an irregular or asymmetric modified first anatomicmodel. Therefore, the drawings merely illustrate one particularembodiment of many possible permutations of a modified first bone model.

FIG. 29 illustrates the second (distal) mesh structure 130 of FIG. 27Bsuperimposed on the modified first anatomic model 138 of FIG. 28. FIG.30 illustrates the first (anterior) mesh structure 128 of FIG. 27Asuperimposed on the modified first anatomic model of FIG. 28. FIG. 31further depicts the modified first anatomic model 138 of FIG. 28according to some embodiments.

In some embodiments, the steps of applying one or more mesh structuresand/or performing one or more sweep functions are unnecessary and a“modified” anatomic model may be created directly as a result of imagingof the patient's anatomy. For instance, in some embodiments, thesoftware or other mechanisms obtaining, controlling and/or processingdata related to the patient's anatomy may be programmed or operate suchthat only certain, limited portions of the anatomy of interest areimaged, such portions corresponding to areas where anatomy contactingportions of the patient-matched instrument are located.

FIGS. 32A and 33A illustrate a surgical instrument blank 140 accordingto some embodiments. In the particular instance shown, the blank 140 isconfigured for use with a distal femur. The blank is generally oversizedin volume so that it may be merged with a modified first anatomic model,such as the modified first anatomic model 138 shown in FIGS. 26-31.Subsequently, the volume of the modified first anatomic model 138 may besubtracted from the volume of the blank 140 to produce a patient-matchedsurgical instrument according to embodiments of the invention. In otherembodiments, however, such as but not limited to the alternativeembodiment discussed in the previous paragraph, the blank may begenerally undersized such that material (or “virtual” material) is nottaken away from it to create a patient-matched instrument but thatmaterial is added to it to define patient specific anatomy contactingportions on the anatomy facing face or faces of the instrument.

FIG. 32A shows a superior view of a patient-matched surgical instrumentblank 140, and FIG. 33A shows a posterior isometric view of the blank140. In both figures, a virtual intersection boundary 142 issuperimposed, which represents an outer boundary of the volumetricintersection between the blank 140 and the modified first anatomic model138 of FIG. 28.

FIGS. 32B and 33B illustrate the surgical instrument blank 140 of FIG.32A, but instead of a virtual intersection boundary being superimposedthereon, a first mesh structure 128 is shown to be superimposed inrelation to the blank 140 as it is applied to a first portion of thefirst anatomic model 126. In the particular instance shown, the firstmesh structure 128 is an anterior mesh structure (as shown in FIG. 27A)that is applied to a portion of the first anatomic model 126representing an anterior portion of a distal femur.

FIGS. 32C and 33C illustrate the surgical instrument blank 140 of FIG.32A with a second mesh structure 130 superimposed in relation to theblank 140 as it is applied to a second portion of a first anatomic model126. In the particular instance shown, the second mesh structure 130 isa distal mesh structure (as shown in FIG. 27B) that is applied to aportion of the first anatomic model 126 representing distal condylar andintercondylar portions of a distal femur.

FIGS. 34 and 35 illustrate a method step of merging a surgicalinstrument blank 140 with a modified first anatomic model 138, and thensubtracting the volume of said modified first anatomic model 138 from avolume of the surgical instrument blank 140. During the subtractionfunction in a CAD software package, the surgical instrument blank 140 isessentially transformed into a patient-matched surgical instrumenthaving one or more anatomy-contacting portions as shown and describedfor instance in FIGS. 1-25.

FIGS. 36-38 show an alternative embodiment of a modified first anatomicmodel 144, similar to that which is used to create a patient-matchedsurgical instrument 10 having the anatomy contacting portions 28 shownin FIGS. 1-8.

FIG. 39 illustrates a method step of merging a surgical instrument blank146 with the modified first anatomic model 144 shown in FIGS. 36-38,before subtracting the volume of said modified first anatomic model 144from the surgical instrument blank 146. After the subtraction functionis executed within the CAD software package, the blank 146 istransformed into a patient-matched surgical instrument similar to theone shown in FIGS. 1-8.

FIG. 40 illustrates a method step of simultaneously merging first andsecond surgical instrument blanks 148 and 150 with modified first andsecond anatomic models 152 and 154, respectively. In the particularembodiment shown, the first modified anatomic model 152 is a distalfemur model integrated with a plurality of expanded mesh structures ofclosely interwoven cylindrical struts or tubes, the negatives of whichdefine the geometries and locations of patient specific pads on thesurgical instrument. The second modified anatomic model 154 is aproximal tibia model integrated with a plurality of expanded meshstructures of closely interwoven cylindrical struts.

FIG. 41 illustrates modified first and second anatomic models 152 and154 according to the embodiment shown in FIG. 40. One or more sweepfunctions are executed for a plurality of mesh structures which havebeen applied to, projected onto, or “wrapped” over first and secondanatomic models. In the particular embodiment shown, a small-radiuscylinder is chosen as the cross-sectional profile to be applied to eachstrut within the mesh structures, a distal femur has been chosen as thefirst anatomic model, and a proximal tibia has been chosen as the secondanatomic model. As shown in the figure, the sweep function need not beapplied to an entire mesh structure and/or overlapping sections of meshstructures. Rather, it may be desirable in some instances to performsweep functions in only select areas of the mesh structures. In somecases, such as for the embodiment shown in FIG. 17A, it may be desirableto increase the size or cross-sectional geometries of portions of themesh structures (e.g., central areas of the mesh structures) in order tostagger, displace, or effectively remove some anatomy contactingportions 108 from desired regions of the patient-matched surgicalinstrument.

FIG. 42A illustrates a second mesh structure 156 (in bold) used tocreate the modified first anatomic model 152 shown in FIGS. 40 and 41.In the particular embodiment shown, the second mesh structure 156 is adistal femoral mesh structure which is applied to a distal femoralanatomic model proximate condylar and intercondylar regions.

FIG. 42B illustrates a first mesh structure 158 (in bold) used to createthe modified first anatomic model 152 shown in FIGS. 40 and 41. In theparticular embodiment shown, the first mesh structure 158 is an anteriorfemoral mesh structure which is applied to an anterior portion of adistal femoral anatomic model adjacent the anterior femoral cortex andtrochlear groove.

FIG. 43A illustrates a second mesh structure 160 (in bold) used tocreate the modified second anatomic model 154 shown in FIGS. 40 and 41.In the particular embodiment shown, the second mesh structure 160 is aproximal tibial mesh structure which is applied to a proximal tibialanatomic model proximate the medial and lateral sulcus portions of thetibial plateau.

FIG. 43B illustrates a first mesh structure 162 (in bold) used to createthe modified first anatomic model 154 shown in FIGS. 40 and 41. In theparticular embodiment shown, the first mesh structure 162 is an anteriortibial mesh structure that is applied to an anterior cortex portion of aproximal tibial model adjacent the tibial tubercle.

FIGS. 44 and 45 further illustrate a method step of merging a secondsurgical instrument blank 150 with a modified second anatomic model 154,and then subtracting a volume of said modified second anatomic model 154from the volume of the second surgical instrument blank 150 to create amodel of a patient-matched surgical instrument. In the particularembodiment shown, the patient-matched surgical instrument is a customtibial cutting jig similar to the one shown in FIGS. 15-16. FIGS. 44 and45 are derived from FIG. 40, showing only the modified second anatomicmodel 154 with the second surgical instrument blank 150 for clarity.

In some embodiments, one or more of the above described steps may beperformed using computer equipment, whether stand alone or networked.Such computer equipment, in some embodiments, may include memory, aprocessor, and input/output features, which may facilitate performing atleast some of the above identified steps, including creating one or morebone models, applying a mesh or meshes to such bone models, performing asweep function on the mesh as applied to the bone model, merging a blankto the modified bone model, performing a subtraction function to definea patient specific instrument, and other functions. In some embodiments,the computer equipment may include or may be associated with a databasein which is stored data about one or more mesh constructs, blanks, orother data. Some embodiments may include communication functionality toallow surgeons to remotely upload information about a patients' anatomy,and/or to participate or be able to provide feedback on a patientspecific instrument.

While the instruments and methods shown and described are generallyshown as configured for use in knee arthroplasty procedures, it isanticipated that the various anatomy-contacting portions and patternsthereof described herein may be applied to surgical instrumentsconfigured for use in other procedures. For instance, features of thedescribed instruments and manufacturing methods thereof may be utilizedwith surgical instruments configured for contacting portions of afemoral head, acetabulum, glenoid, humerus, radius, ulna, fibula, tibia,proximal femur, foot, ankle, wrist, extremity, or other bony orcartilaginous regions.

As various modifications could be made to the exemplary embodiments, asdescribed above with reference to the corresponding illustrations,without departing from the scope of the inventions described herein, itis intended that all matter contained in the foregoing description andshown in the accompanying drawings shall be interpreted as illustrativerather than limiting. Thus, the breadth and scope of the inventionshould not be limited by any of the above-described exemplaryembodiments.

1. A method of designing a surgical instrument matched to a particularanatomic structure, wherein the surgical instrument comprises an anatomyfacing side including at least one anatomy contacting portion and atleast one recessed portion that is recessed relative to parts of the atleast one anatomy contacting portion proximate the at least one recessedportion, the method comprising: (a) accessing a three-dimensionalcomputer model of the anatomic structure, the three-dimensional computermodel of the anatomic structure including at least one portioncorresponding to the at least one anatomy contacting portion of thesurgical instrument; (b) using a computer comprising a processor,modifying the three-dimensional computer model of the anatomic structureto create a modified three-dimensional computer model including at leastone portion corresponding to the at least one recessed portion of thesurgical instrument; and (c) using the modified three-dimensionalcomputer model of the anatomic structure to modify a computer model ofan instrument blank to correspond to the surgical instrument.
 2. Themethod of claim 1, wherein modifying the three-dimensional computermodel of the anatomic structure comprises creating a raised portion onthe three-dimensional computer model of the anatomic structure.
 3. Themethod of claim 1, wherein modifying the three-dimensional computermodel of the anatomic structure comprises positioning a mesh relative tothe three dimensional computer model of the anatomic structure.
 4. Themethod of claim 3, further comprising creating an expanded mesh from themesh.
 5. The method of claim 3, wherein positioning the mesh comprisespositioning a first mesh relative to an anterior portion of thethree-dimensional computer model of the anatomic structure andpositioning a second mesh relative to a distal portion of thethree-dimensional computer model of the anatomic structure, wherein thethree dimensional computer model is a model of a distal femur.
 6. Themethod of claim 3, wherein positioning the mesh comprises wrapping themesh around a portion of the three dimensional computer model of theanatomic structure.
 7. The method of claim 3, wherein positioning themesh comprises positioning a mesh having a uniform grid pattern.
 8. Themethod of claim 1, wherein accessing the three-dimensional computermodel of the anatomic structure comprises accessing a three-dimensionalcomputer model of an anatomic structure of a particular patient.
 9. Themethod of claim 1, wherein using the modified three-dimensional computermodel of the anatomic structure to modify the computer model of theinstrument blank comprises merging the computer model of the instrumentblank with the modified three-dimensional computer model of the anatomicstructure.
 10. The method of claim 9, wherein using the modifiedthree-dimensional computer model of the anatomic structure to modify thecomputer model of the instrument blank further comprises subtracting anintersecting volume of the modified three-dimensional computer model ofthe anatomic structure from a volume of the computer model of theinstrument blank.
 11. The method of claim 1, further comprisingmanufacturing the surgical instrument.
 12. The method of claim 1,further comprising outputting the modified computer model of theinstrument blank to a device configured to manufacture the surgicalinstrument.
 13. The method of claim 1, wherein modifying the computermodel of the instrument blank comprises removing portions from acomputer model of an oversized instrument blank.
 14. The method of claim1, wherein modifying the computer model of the instrument blank tocorrespond to the surgical instrument comprises modifying the computermodel of the instrument blank to correspond to a surgical instrumentcomprising a plurality of discrete, physically separate anatomycontacting portions, wherein the plurality of anatomy contactingportions are at least one of: (i) non-uniform in distribution; (ii)non-uniform in shape; or (iii) non-uniform in surface area.
 15. Themethod of claim 1, wherein modifying the computer model of theinstrument blank to correspond to the surgical instrument comprisesmodifying the computer model of the instrument blank to correspond to asurgical instrument wherein the at least one anatomy contacting portiondefines a first total area of the anatomy facing side and wherein the atleast one recessed portion defines a second total area of the anatomyfacing side; wherein the second total area is greater than the firsttotal area.
 16. A method of designing a surgical instrument matched to aparticular anatomic structure, wherein the surgical instrument comprisesan anatomy facing side including at least one anatomy contacting portionand at least one recessed portion that is recessed relative to parts ofthe at least one anatomy contacting portion proximate the at least onerecessed portion, the method comprising: (a) accessing athree-dimensional computer model of the anatomic structure, thethree-dimensional computer model of the anatomic structure including atleast one portion corresponding to the at least one anatomy contactingportion of the surgical instrument; (b) using a computer comprising aprocessor, modifying the three-dimensional computer model of theanatomic structure to create a modified three-dimensional computer modelincluding at least one portion corresponding to the at least onerecessed portion of the surgical instrument, wherein modifying thethree-dimensional computer model of the anatomic structure comprisespositioning a mesh relative to the three dimensional computer model ofthe anatomic structure; and (c) using the modified three-dimensionalcomputer model of the anatomic structure to modify a computer model ofan instrument blank to correspond to the surgical instrument.
 17. Themethod of claim 16, wherein positioning the mesh comprises positioning afirst mesh relative to an anterior portion of the three-dimensionalcomputer model of the anatomic structure and positioning a second meshrelative to a distal portion of the three-dimensional computer model ofthe anatomic structure, wherein the three dimensional computer model isa model of a distal femur.
 18. The method of claim 16, whereinpositioning the mesh comprises wrapping the mesh around a portion of thethree dimensional computer model of the anatomic structure.
 19. Themethod of claim 16, wherein positioning the mesh comprises positioning amesh having a uniform grid pattern.
 20. A method of designing a surgicalinstrument matched to a particular anatomic structure, wherein thesurgical instrument comprises an anatomy facing side including at leastone anatomy contacting portion and at least one recessed portion that isrecessed relative to parts of the at least one anatomy contactingportion proximate the at least one recessed portion, the methodcomprising: (a) accessing a three-dimensional computer model of theanatomic structure, the three-dimensional computer model of the anatomicstructure including at least one portion corresponding to the at leastone anatomy contacting portion of the surgical instrument; (b) using acomputer comprising a processor, modifying the three-dimensionalcomputer model of the anatomic structure to create a modifiedthree-dimensional computer model including at least one portioncorresponding to the at least one recessed portion of the surgicalinstrument, wherein modifying the three-dimensional computer model ofthe anatomic structure comprises positioning a mesh relative to thethree dimensional computer model of the anatomic structure; (c) usingthe modified three-dimensional computer model of the anatomic structureto modify a computer model of an instrument blank to correspond to thesurgical instrument by: (i) merging the computer model of the instrumentblank with the modified three-dimensional computer model of the anatomicstructure; and (ii) subtracting an intersecting volume of the modifiedthree-dimensional computer model of the anatomic structure from a volumeof the computer model of the instrument blank; and (d) outputting themodified computer model of the instrument blank to a device configuredto manufacture the surgical instrument.